Input device having push-keys, and image forming apparatus having the same

ABSTRACT

A push type key includes a base including a main body, a key portion having an operation surface, first and second elastic portions connecting between the main body and the key portion, and an electrical equipment substrate provided on a back side of the base. The substrate includes an operating portion acted on by the key portion when the key portion moves. The first and second elastic portions have symmetrical configurations with respect to a phantom line passing through a center of the key portion, as seen perpendicularly to the operation surface. The operating portion is disposed at a position closer to the first elastic portion than to the second elastic portion. The base is provided with a third elastic portion connecting the key portion with the main body or with the second elastic portion in a side of the second elastic portion with respect to the phantom line.

FIELD OF THE INVENTION AND RELATED ART

The present invention relates to an input device for a user to operatean apparatus. It relates to also an image forming apparatus such as acopying machine, a printer, or the like, which is equipped with theinput device.

Here, an image forming apparatus is an apparatus for forming an image onrecording medium with the use of an electrophotographic method, forexample. As for examples of electrophotographic image forming apparatus,they include electrophotographic copying machines, electrophotographicprinting machines (laser beam printer, LED printers, and the like),facsimile machines, word processors, and the like.

Some image forming apparatuses are equipped with an input device havingpush-keys which are to be used by a user to operate the apparatus. As apush-key is pressed by a user, a corresponding switch within the inputdevice is turned on or off so that a control section of the imageforming apparatus detects the pressed key, and carries out a processwhich corresponds to the pressed key.

Generally speaking, an input device having push-keys has: a base memberhaving key portions which a user touches; and an electric circuit boardhaving portions (switches or the likes) on which the keys act. It isstructured so that the base member is laid upon the electric circuitboard. The base member is molded of resin, in one-piece. The keyportions of the base member are in connection to a main portion of thebase member through branch-like elastic portions. The input device isstructured so that as a user presses one of the key portions, theelastic portions deform relative to the main portion of the base member,allowing thereby the key portion to act on the switch or the like on theelectric circuit board (Japanese Laid-open Patent Application No.2008-299444).

There is also known an input device having such keys that can beilluminated to inform a user of the state of an apparatus, degree ofprogression of an on-going operation, and/or the like. Its electricalcircuit board is provided with light emitting elements such as LEDs. Itis structured so that the keys are illuminated with the LEDs or the likefrom within the keys (Japanese Laid-open Patent Application No.2004-281210).

By the way, in order to make the luminous keys better in visibilitywhile they are illuminated, it is desired to position a light emittingelement such as an LED directly below the portion of the luminous key,which is to be illuminated. Further, for the reason related to design,many input devices are structured so that the area of the key, which isto be illuminated, coincides with the center portion of the key.

In the case of an input device structured as described above, a lightemitting element is disposed directly below the center portion of thekey. Therefore, the switch which is to be pressed by the pressureapplying portion of the key cannot be placed directly below the centerportion of the key. Thus, the key feels inferior in tactility.

As described above, in the case of an input device structured so that a“switch or the like, to which pressure is applied by the key” cannot beplaced directly below the center portion of the key, there is an issuethat the key is inferior in tactility. By the way, even if an apparatusdoes not employ luminous keys, as long as it is structured so that itsportion to which pressure is applied by the key cannot be positioneddirectly below the center portion of the key, it suffers from the sameissue as the abovementioned input devices for an image formingapparatus.

SUMMARY OF THE INVENTION

The present invention was made in consideration of the above-describedissue. Thus, the primary object of the present invention is to providean input device having push-keys which feel better to a user intactility as the user presses the keys than a conventional input device.It is also to provide an image forming apparatus having the inputdevice.

According to an aspect of the present invention, there is provided aninputting device having a push type key, said inputting devicecomprising a base member including a main body portion, a key portionhaving an operation surface to be pushed by an operator, a first elasticportion and a second elastic portion which connect between said mainbody portion and said key portion; and an electrical equipment substrateprovided on a back side of said base member, said electrical equipmentsubstrate including an operating portion acted on by said key portionwhen said key portion moves; wherein said first and second elasticportions have symmetrical configurations with respect to a phantom linepassing through a central portion of said key portion, as seen in adirection perpendicular to said operation surface, wherein saidoperating portion is disposed at a position closer to said first elasticportion than to said second elastic portion, and wherein said basemember is provided with a third elastic portion connecting said keyportion with said main body portion or with said second elastic portionin a side of said second elastic portion with respect to the phantomline.

Further features of the present invention will become apparent from thefollowing description of exemplary embodiments with reference to theattached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an example of an image forming apparatusto which the present invention is applicable.

FIG. 2 is a schematic sectional view of the image forming apparatusshown in FIG. 1.

Part (a) of FIG. 3 and part (b) of FIG. 3 are perspective views of aninput device in a first embodiment before and after, respectively, thedisassembling of the input device. They are for describing the structureof a key portion of the input device.

Parts (a) and (b) of FIG. 4 are perspective views of the input deviceand its top cover. They are for describing how the input device isattached to the top cover.

Part (a) of FIG. 5 is a top view of an input key member of the inputdevice, and part (b) of FIG. 5 is a sectional view of one of a luminouskey portion, and its adjacencies, of the input device.

Part (a) of FIG. 6 is a top view of a key portion of a comparative inputdevice, and part (b) of FIG. 6 is a sectional view of one of a luminouskey portion.

Part (a) of FIG. 7 is a sectional view of one of the key portions of thecomparative input device, when the key portion is being pressed, andpart (b) of FIG. 7 is a sectional view of one of the luminous keyportions of the input device in this embodiment, when a switch sectionof the input device is being pressed by the key portion.

FIG. 8 is a top view of an input key member in another embodiment of thepresent invention.

FIG. 9 is an exploded perspective view of the input device in anotherembodiment of the present invention. It is for describing the structureof an input key member.

FIG. 10 is an exploded view of the input device in another embodiment ofthe present invention. It is for describing the structure of an inputkey member.

DESCRIPTION OF THE EMBODIMENTS

Hereinafter, a few of the preferable embodiments of the presentinvention are described in detail. However, the measurements, materials,and shapes of the structural components of the input devices and imageforming apparatuses in the following embodiments of the presentinvention, and their positional relationship among them, are notintended to limit the present invention in scope, unless specificallynoted. They are to be modified as necessary according to the structureof the apparatus to which the present invention is applied, and also,various conditions under which the apparatuses are operated.

Embodiment 1

First, referring to FIGS. 1-7(b), an image forming apparatus in a firstembodiment of the present invention is described.

By the way, electrophotographic image forming apparatuses in thefollowing embodiments of the present invention are electrophotographicfull-color image forming apparatuses, in which four process cartridgesare removably installable. However, the following embodiments are notintended to limit the present invention in the number of processcartridges which the apparatuses employ for the formation of afull-color image. That is, the number is set as necessary. For example,when the apparatuses are used for forming a monochromatic image, thenumber of process cartridge which the apparatuses employ is one.

Further, the image forming apparatus in each of the followingembodiments which will be described hereafter is a printer. However,these embodiments are not intended to limit the present invention in thetype of image forming apparatus to which the present invention isapplicable. That is, the present invention is also applicable to otherimage forming apparatuses than printers. For example, the presentinvention is applicable to copying machines, facsimileing machines, andmultifunction machines capable of performing functions of two or more ofthe abovementioned machines.

(General Structure of Image Forming Apparatus)

To begin with, an image forming apparatus 1 to which the presentinvention is applicable is described about its general structure. FIG. 1is an external perspective view of the image forming apparatus 1 in thisembodiment. FIG. 2 is a schematic sectional view of the image formingapparatus 1 in this embodiment.

This image forming apparatus 1 is a full-color laser printer based onfour primary colors. It forms a color image on a sheet S of recordingmedium with the use of an electrophotographic process. It has an imageforming portion structured as follows. That is, it employs a processcartridge system. It is structured so that process cartridges (whichhereafter may be referred to simply as cartridges) are removablyinstallable in its main assembly 2.

Here, regarding the orientation of the image forming apparatus 1, theside having a door 3 is referred to as “front” side, and the oppositeside from the front side is referred to as “rear” (back) side. Further,the right side of the image forming apparatus 1 as seen from the frontside is referred to as “drive” side, whereas the left side is referredto as “non-drive” side.

In the main assembly 2 of the image forming apparatus 1, fourcartridges, more specifically, first to fourth cartridges PY, PM, PC andPK are removably mountable in such a manner that they horizontallyalign. It is structured so that as the door 3 is opened, a cartridgetray 24 can be pulled out frontward from the main assembly 2 through anopening 30 of the apparatus main assembly 2 to replace the cartridgesPY, PM, PC and PK. To the first to fourth cartridges (PY, PM, PC andPK), rotational driving force is transmitted from a driving force outputportion (unshown) of the main assembly 2. Further, to each of the firstto fourth cartridges (PY, PM, PC and PK), bias voltages (charge bias,development bias, and the like) are supplied from the bias voltagesources (unshown) of the main assembly 2.

Each of the first to fourth cartridges (PY, PM, PC and PK) has its ownelectrophotographic image forming system. The four cartridges aresimilar in structure, although they are different in the color of thedeveloper (which hereafter may be referred to as toner) they use. Thefirst cartridge PY contains yellow (Y) toner. It forms a yellow (Y)toner image on the peripheral surface of a photosensitive drum 40. Thesecond cartridge PM contains magenta (M) toner. It forms a magenta (M)toner image on the peripheral surface of the photosensitive drum 40. Thethird cartridge PC contains cyan (C) toner. It forms a cyan (C) tonerimage on the peripheral surface of the photosensitive drum 40. Thefourth cartridge PK contains black (K) toner. It forms a black (K) tonerimage on the peripheral surface of the photosensitive drum 40.

Above the combination of the first to fourth cartridges (PY, PM, PC andPK), a laser scanner unit LS is provided as an exposing means. Thislaser scanner unit LS outputs a beam Z of laser light while modulatingthe beam Z according to the information of the image to be formed. Asthe beam Z of laser light is outputted, it projects through an exposurewindow of the cartridge P, and scans (exposes) the peripheral surface ofthe photosensitive drum 40.

Below the combination of the first to fourth cartridges (PY, PM, PC andPK), an intermediary transfer unit 11 is disposed as a transferringmember. The intermediary transfer unit 11 has a driver roller 13, a turnroller 17, and a tension roller 15. It has also a flexible transfer belt12, which is suspended by the abovementioned three rollers 13, 17 and15.

The photosensitive drum 40 of each of the first to fourth cartridges(PY, PM, PC and PK) is in contact with the upwardly facing portion ofthe outwardly facing surface of the transfer belt 12. The area ofcontact between the photosensitive drum 40 and transfer belt 12 is aprimary transfer portion. On the inward side of the loop which thetransfer belt 12 forms, four primary transfer rollers 16 are disposed sothat they oppose the four photosensitive drums 40 one for one.

Against the turn roller 17, a secondary transfer roller 14 is keptpressed with the presence of the transfer belt 12 between the tworollers 17 and 14. The area of contact between the transfer belt 12 andsecondary transfer roller 14 is a secondary transfer portion.

Below the intermediary transfer unit 11, a sheet feeding-conveying unit18 is disposed. This sheet feeding-conveying unit 18 has a sheetfeeding-conveying tray 19 in which sheets S of recording medium arestored in layers, and a sheet feeding-conveying roller 20 which feedsthe sheets S from the sheet feeding-conveying tray 19 into the mainassembly 2, one by one, and conveys each sheet S further into the mainassembly 2.

Referring to FIG. 2, in the top-left portion of the main assembly 2, afixation unit 21 and a discharge unit 22 are disposed. A part of the topsurface of the main assembly 2 is utilized as a delivery tray 23. Aseach sheet S of recording medium is conveyed through the abovementionedfixation unit 21, the toner image on the sheet S is fixed to the sheet Sby a fixing means, with which the fixation unit 21 is provided. Then,the sheet S is discharged by the discharge unit 22 into theabovementioned delivery tray 23.

Next, the operation carried out by the image forming apparatus 1structured as described above to form a full-color image is described.

The photosensitive drum 40 in each of the first to fourth cartridges(PY, PM, PC and PK) is rotationally driven at a preset speed (directionindicated by an arrow mark in FIG. 2; counterclockwise direction). Thetransfer belt 12 is rotationally driven so that it moves in the samedirection (direction indicated by arrow mark C in FIG. 2) in the area ofcontact between photosensitive drum 40 and transfer belt 12 at a speedwhich corresponds to the speed of the photosensitive drum 40.

The laser scanner unit LS scans (exposes) the peripheral surface of eachphotosensitive drum 40 with the beam Z of laser light it emits whilemodulating the beam Z with image formation signals which correspond tomonochromatic images into which the image to be formed was separated.Consequently, an electrostatic latent image, which reflects the imageformation signals, is effected on the peripheral surface of thephotosensitive drum 40. Then, the latent image is developed by adevelopment roller 42, which is in a developing device 41 and isrotationally driven at a preset speed.

Through an electrophotographic image formation process such as theabove-described one, a yellow (Y) toner image, which corresponds to theyellow component of the full-color image to be formed, is formed on theperipheral surface of the photosensitive drum 40 in the first cartridgePY. This toner image is transferred (primary transfer) onto the transferbelt 12.

Similarly, on the photosensitive drum 40 of the second cartridge PM, amagenta (M) toner image which corresponds to the magenta (M) componentof the full-color image to be formed, is formed. This toner image istransferred (primary transfer) onto the transfer belt 12, in a manner tobe layered upon the yellow (Y) toner image which has just beentransferred onto the transfer belt 12.

Similarly, on the photosensitive drum 40 of the third cartridge PC, acyan (C) toner image which corresponds to the cyan (C) component of thefull-color image to be formed, is formed. This toner image istransferred (primary transfer) onto the transfer belt 12, in a manner tobe layered upon the yellow (Y) and magenta (M) toner images, which havejust been transferred onto the transfer belt 12.

Similarly, on the photosensitive drum 40 of the fourth cartridge PK, ablack (K) toner image which corresponds to the black (K) component ofthe full-color image to be formed, is formed. This toner image istransferred (primary transfer) onto the transfer belt 12, in a manner tobe layered upon the yellow (Y), magenta (M), and cyan (C) toner images,which have just been transferred onto the transfer belt 12.

Consequently, an unfixed full-color toner image is synthetically formedof yellow (Y), magenta (M), cyan (C), and black (K) monochromaticimages, on the transfer belt 12.

Meanwhile, the sheet feeding-conveying roller 20 begins to be drivenwith preset timing, whereby the sheets S stored in layers in the sheetfeeding: conveying tray 19 begin to be fed into the main assembly 2,while being separated one by one, and to be guided into the secondarytransfer nip, which is the area of contact between the secondarytransfer roller 14 and transfer belt 12, to be conveyed through the nip.

While each sheet S of recording medium is conveyed through the secondarytransfer nip, the four toner images which are different in color and arelayered on the transfer belt 12 are transferred together onto the sheetS as if they are peeled away from the transfer belt 12.

Next, an input device (input device having push-keys) is described aboutits structure. Referring to FIG. 1, the main assembly 2 of the imageforming apparatus 1 is provided with an input device A through which theimage forming apparatus 1 receives inputs from a user. The input deviceA is disposed so that its top surface is exposed upward. In thisembodiment, the input device A is an integral part of a top cover 80 ofthe main assembly 2.

The input device A is provided with a display 74, and keys 51, 52 b, 52c and 53 d which are operable by a user. Among the four keys, the key 51can be illuminated from its inward side. It is for a user to connect theimage forming apparatus 1 to a wireless LAN, or disconnect the imageforming apparatus 1 from the wireless LAN. That is, as the key 51 ispressed once by a user, not only is the image forming apparatus 1connected to the wireless LAN, but also, the key 51 is illuminated toconfirm that the image forming apparatus 1 is in connection to thewireless LAN. On the other hand, as the key 51 is pressed while the key51 is luminous, the key 51 stops being luminous, and the image formingapparatus 1 becomes disconnected from the wireless LAN. Disconnectingthe image forming apparatus 1 from the wireless LAN reduces the imageforming apparatus 1 in electric power consumption.

Referring to parts (a) and (b) of FIG. 3 and parts (a) and (b) of FIG.4, the input device A is an assembly of an input key member 50 (basemember), and an electric circuit board 70 on which the input key member50 is layered. The entirety of the input key member 50 (base member) ismolded in one-piece, of a resinous substance. It has a main portion 50h, and key portions 51, 52 b, 52 c and 52 d having an area to be pressedby a user. Each key portion 51, 52 b, 52 c and 52 d is connected to themain portion 50 h with elastic portions, as will be described later. Thecircuit electric board 70 is provided with switches (on which keyportions act) 71 a-71 f, four of which correspond to the key portions51, 52 b, 52 c and 52 d, respectively, and a light emitting element 72for illuminating the luminous key portion 51. The switches 71 a-71 f aresensors that detect whether or not the corresponding key portions 51, 52b, 52 c and 52 d have just been pressed. One of these switches, morespecifically, the switch 71 a, corresponds to the luminous key portion51. The switch 71 b corresponds to the key portion 52 b. The switch 71 ccorresponds to the key portion 52 c. The switch 71 d corresponds to thekey portion 52 d. The switches 71 e and 71 f correspond to amultifunction input key 60. As any of these keys is pressed by a user,the input device A informs the control portion (unshown) which input keyhas just been pressed. Then, the control portion presents theinformation related to the pressed key on a display 74. Further, itdisplays on the display 74, information regarding whether or not theimage forming apparatus 1 is in connection to the wireless LAN, inresponse to whether or not the light emitting element 72 is on (whetheror not switch 71 a is on). With use of the input device A, a user canconversationally choose various functions of the image forming apparatus1.

Referring to part (a) of FIG. 5, the main portion 50 h of the input keyportion member 50 (base member) is connected to the luminous key portion51 and non-luminous key portions 52 b-52 d by elastic portions 57 a 1,57 a 2-57 d. That is, the main portion 50 h, key portions 52 b-52 d, andelastic portions 57 a-57 d are integral parts of a one-piece component.All the key portions except for the luminous key portion 51 areconnected to the main portion 50 h by two elastic portions. Morespecifically, the key portion 52 b is connected to the main portion 50 hby two elastic portions 57 b. The key portion 52 c is connected to themain portion 50 h by two elastic portions 57 c. The key portion 52 d isconnected to the main portion 50 h by two elastic portions 57 d. To themain portion 50 h, the base portion of each elastic portion isconnected. As a key portion is pressed, the corresponding elasticportions elastically deform, allowing the key to move relative to themain portion 50 h to press on the corresponding switch.

The key portion 51 is connected to the main portion 50 h by first andsecond elastic portions 57 a 1 and 57 a 2. As the key portion 51 is seenfrom the direction which is perpendicular to a control panel 51P, thefirst and second elastic portions 57 a 1 and 57 a 2 are symmetricallyshaped and positioned with reference to a hypothetical line L51 whichcoincides with a center C51 of the key portion 51. In this embodiment,other elastic portions 57 a 1, 57 a 2-57 d are also symmetrically shapedand positioned with reference to a hypothetical line which coincideswith the center of the corresponding key.

Further, the surface of the input key member 50 (base member), whichfaces the electric circuit board 70, is provided with pressing sections53 a-53 d for pressing down the switches 71 a-71 d. The pressing section53 a is for pressing the switch 71 a, and the pressing section 53 b isfor pressing the switch 71 b. The pressing section 53 c is for pressingthe switch 71 c, and the pressing section 53 d is for pressing theswitch 71 d. Also, the pressing section 53 e is for pressing the switch71 e, and the pressing section 53 f is for pressing the switch 71 f.

Referring to parts (a) and (b) of FIG. 4, the input key member 50 (basemember) having keys has first positioning holes 55 a and 55 b, whereasthe top cover 80 has positioning bosses 85 a and 85 b. As the input keymember 50 (base member) is attached to the top cover 80 so that thepositioning bosses 85 a and 85 b fit into the first positioning holes 55a and 55 b, respectively, the input key member 50 (base member) isprecisely positioned relative to the top cover 80.

Further, the electrical circuit board 70 has second positioning holes 75a and 75 b. As the electrical circuit board 70 is attached to the topcover 80 so that the positioning bosses 85 a and 85 b fit into thesecond positioning holes 75 a and 75 b, the electrical circuit board 70is precisely positioned relative to the top cover 80.

Referring to parts (a) and (b) of FIG. 3, and parts (a) and (b) of FIG.4, the multifunction input key 60 is provided with a pair of rotationalshafts 66 a and 66 b, and a pair of pressing sections 63 e and 63 f.Referring to part (a) of FIG. 3, the input key member 50 is providedwith a pair of bearings 56 a and 56 b, which correspond to therotational shafts 66 a and 66 b of the multifunction input key 60, andby which the rotational shafts 66 a and 66 b are borne, respectively. Asthe left or right side of the multifunction input key 60 is pressed, themultifunction input key 60 pivotally moves about the rotational shafts66 a and 66 b, becoming thereby tilted. Consequently, the switches 71 eand 71 f on the electrical circuit board 70 are pressed down by thepressing sections 63 e or 63 f, respectively.

Next, the structure of the luminary (or luminous) key portion 51 isdescribed in detail. Part (a) of FIG. 5 is a top view of the input keymember 50, and part (b) of FIG. 5 is a sectional view of the input keymember 50. Part (a) of FIG. 5 shows the pressing section 53 a, switch 71a, and light emitting element 72, which are contoured by broken lines.

The center portion of the luminary key portion 51 is provided with around transparent area B, which is formed of transparent resin. On theother hand, other portions (main portion 50 h, key portions 51, 52 b, 52c, 52 d) of the input key member 50 (base member) than the centerportion of the luminary key portion 51 are formed of opaque resin. Thetransparent area B is formed as an integral part of the input key member50 (base member), which is molded in one-piece. In this embodiment, thematerial for the transparent area B of the input key member 50 (basemember) is PS (Polyester), whereas the material for the other portions(opaque portions) of the input key member 50 (base member) is ABS(Acrylonitrile Butadiene, Styrene).

The light emitting element 72 on the electric circuit board 70 isdirectly below the transparent area B of the luminary key portion 51.More specifically, the light emitting element 72 is positioned so thatin terms of the direction perpendicular to the control panel 51P, thecenter of the light emitting element 72 aligns with the center of thecenter C51 of luminary key portion 51. Therefore, the switch 71 a andpressing section 53 a, which correspond to the luminary key portion 51,cannot be positioned directly below the luminary key portion 51. Thatis, as the luminary key portion 51 is seen from the directionperpendicular to the control panel 51P, the light emitting element 72 ispositioned closer to the center C51 of the luminary key portion 51 thanthe switch 71 a (on which pressing section 53 a acts). Therefore, theswitch 71 a and pressing section 53 a, which correspond to the luminarykey portion 51, are positioned so that they are offset leftward relativeto the light emitting element 72, as shown in part (a) of FIG. 5. Alsoas the luminary key portion 51 is seen from the direction perpendicularto the control panel 51P, the switch 71 a (on which pressing section 53a acts) is positioned so that it is closer to the first elastic portion57 a 1 than the second elastic portion 57 a 2.

Further, the luminary key portion 51 is supported not only by the firstand second elastic portions 57 a 1 and 57 a 2, but also, by an elasticportion 58 a (third elastic portion), which is the hatched portion inthe drawing. Here, the first and second elastic portions 57 a 1, 57 a 2,and the elastic portions 57 b-57 d which support the input keys 52 b-52d, are shaped and positioned so that they are symmetrical with referenceto either a vertical line which coincides with the center of thecorresponding key, or a horizontal line which coincides with center ofthe corresponding key. In comparison, there is no elastic portion whichis shaped and positioned to be symmetrical with reference to a verticalor horizontal line which coincides with the center of the correspondingkey. In this embodiment, the third elastic portion 58 a is positioned toconnect the key portion 51 to the second elastic portion 57 a 2.However, it may be positioned to connect the key portion 51 to the mainportion 50 h. When all is said and done, the input key member 50 (basemember) is provided with the third elastic portion 58 a, which connectsthe key portion 51 to the main portion 50 h or the second elasticportion 57 a 2. Further, the third elastic portion 58 a is on the secondelastic portion 57 a 2 side of the hypothetical line L51.

Here, it is desired that the length L2 of the third elastic portion 58 ais less than the length L1 of the first elastic portion 57 a 1 (57 a 2).The provision of the third elastic portion 58 a (which preferablysatisfies inequality: L1>L2) increases in rigidity, the elastic portion(on second elastic portion 57 a 2 side) which is on the opposite sidefrom the pressing section 53 a. Therefore, it is possible to prevent theproblem that as the third elastic portion 58 a is made to press on theswitch 71 a by the pressing of the key portion 51, the key portion 51tilts.

Part (b) of FIG. 5 is a sectional view of the luminary key portion 51and its adjacencies. The luminary key portion 51 is provided with abumping portion 59, which is on the opposite portion of the luminary keyportion 51 from the pressing section 53 a, with reference to thetransparent area B of the luminary key portion 51. Thus, it is possibleto prevent the problem that as the luminary key portion 51 is pressedhard by a user, the switch 71 a is damaged.

At this time, what occurs to the input device A in this embodiment asthe luminary key portion 51 is pressed is described with reference to acomparative example of an input device. Part (a) of FIG. 6 is a top viewof the comparative example of input key member 50, and part (b) of FIG.6 is a sectional view of the comparative example of input key member 50.In the case of the comparative example of input key member 50, it isonly the first and second elastic portions 57 a 1 and 57 a 2 thatsupports the luminary key portion 51 (third elastic portion 58 a is notprovided). Part (a) of FIG. 7 is a sectional view of the luminary keyportion 51 and its adjacencies in the comparative example of inputdevice A, when the luminary key portion 51 is being pressed. Part (b) ofFIG. 7 is a sectional view of the luminary key portion 51 and itsadjacencies in the input device A in this embodiment when the luminarykey portion 51 is being pressed.

In the case of the comparative example of input device A shown in part(a) of FIG. 7, as a user presses on the luminary key portion 51, thepressing section 53 a comes into contact with a part of the switch 71 a,and the luminary key portion 51 is made to pivotally move (tilt) aboutthe point of contact between the pressing section 53 a and switch 71 a.Thus, it is possible that the amount by which force is applied to theswitch 71 a by the pressing section 53 a of the luminary key portion 51will be insufficient, and therefore, the switch 71 a will not respond.In the case of the comparative example of input device A, therefore,unless the luminary key portion 51 is pressed harder (deeper) than thenonluminous key portions 52 b-52 d, the pressing section 53 a does notpress the switch 71 a hard enough to activate the switch 71 a. Thus, auser might feel that the luminary key portion 51 is inferior intactility.

On the other hand, in this embodiment, the luminous key portion 51 issupported by the third elastic portion 58 a in addition to the first andsecond elastic portions 57 a 1 and 57 a 2. Therefore, the input keymember 50 is higher in rigidity across the area which is on the oppositeside (right side in parts (a) and (b) of FIG. 5 of the luminary keyportion 51 from the pressing section 53 a. Therefore, as a user pressesdown the luminary key portion 51, the pressing section 53 a presses onthe top surface of the switch 71 a in the roughly vertical direction.Therefore, the luminary key portion 51 remains the same (excellent) intactility, because the luminary key portion 51 descends with the topsurface of the luminary key portion 51 remaining parallel to theelectric circuit board 70.

As described above, according to this embodiment, it is possible toplace the light emitting element 72 directly below the transparent areaB of the luminary key portion 51. Therefore, it is possible to make theluminary key portion 51 better in terms of how it looks when it isilluminated. Further, the input key member 50 is provided with the thirdelastic portion 58 a which is asymmetrical in shape and positioning, inaddition to multiple elastic portions by which the luminary key portion51 is supported in a conventional input key member. It is possible toprovide an input device which is classier in tactility (usability) thana conventional one, without the cost increase attributable to the needfor additional components.

In the above-described first embodiment, the switch 71 a was placed onthe portion of the electric circuit board 70, which is offset from thecenter C51 of the luminary key portion 51 in terms of the firstdirection, that is, the left-right direction, in part (a) of FIG. 5.Further, in terms of the second direction, that is, the top-bottomdirection, which is perpendicular to the first direction, the switch 71a is positioned so that it aligns with the center C51 of the luminarykey portion 51. However, the first embodiment is not intended to limitthe present invention in terms of the positioning of the luminary keyportion 51 and switch 71 a relative to each other. For example, theswitch 71 a and pressing section 53 a may be asymmetrically positionedwith reference to the center C51 of the luminary key portion 51 in termsof the left-right and/or top-bottom direction. Also in the firstembodiment, a fourth elastic portion 58 b is provided in addition to thethird elastic portion 58 a. Referring to FIG. 8, a center C53 a of thepressing portion (center of portion to be pressed) is positioned on thebottom side of a second hypothetical line L51Y which is perpendicular tothe hypothetical line L51. The third elastic portion 58 a is positionedon the second elastic portion 57 a 2 side of the hypothetical line L51.The fourth elastic portion 58 b is positioned on the opposite side ofthe second hypothetical line L51Y from the center C53 a (center ofswitch 71 a) of the pressing section 53 a. Positioning an additionalthird elastic portion 58 a or the like as described above can furtherimprove the luminary key portion 51 in tactility (how the luminary keyportion 51 feels as user presses the luminary key portion 51).

Also in the above-described first embodiment, the entirety of theluminary key portion 51 is an integral part of the input key member 50(base member) which is molded in one-piece. However, the firstembodiment is not intended to limit the present invention in terms ofhow the luminary key portion 51 is formed. For example, a part 51P1 ofthe luminary key portion 51 may be separately formed from the rest ofthe luminary key portion 51, so that it can be removably attached to therest. Even if the luminary key portion 51 is formed in this manner, theeffects of the first embodiment are the same as those described above.Further, in the case of the input device A shown in FIG. 9, only thetransparent area B of the part 51P1 of the luminary key portion 51 istransparent, whereas the rest of the part 51P1 are opaque. Further, thetransparent portion of the part 51P1 of the luminary key portion 51, andthe opaque portion of the part 51P1 of the luminary key portion 51, aremolded together, of transparent resin and opaque resin, respectively, asintegral parts of the part 51P1 of the luminary key portion 51.Moreover, the part 51P1 of the luminary key portion 51 is provided witha hook-like portion 51F, which engages with the hook-like portion 51P2of the luminary key portion 51 of the input key member 50 (base member)when the luminary key portion 51 is attached to the input key member 50(base member).

FIG. 10 shows another embodiment of the present invention. The input keymember 50 (base member) includes the main portion 50 h and a part 51B ofthe luminary key portion 51, which are molded together as integral partsof the input key member 50 (base member) molded in one-piece. In thecase of this embodiment, however, the center portion of the part 51B ofthe luminary key portion 51 is nothing but a hole H; the part 51B doesnot have the transparent portion. A referential code 51T stands for acomponent which makes up a part of the luminary key portion 51. Thecomponent 51T is formed of a transparent substance, and is shaped like acap. It is attached to a the part 51B of the luminary key portion 51 tocomplete the luminary key portion 51. That is, the luminary key portion51 may be a combination of the opaque part 51B and transparent component51T.

In all the embodiments described above, the keys which are to beilluminated by a light emitting element were provided with the thirdelastic portion. Instead, however, the input device A may be structuredso that the pressing portion of a key which is not illuminated by alight emitting element is positioned closer to the first elastic portionthan to the second elastic portion, and the base member is provided withthe elastic portion which corresponds to this key.

Further, in each of the above-described embodiments, the image formingapparatus was a printer. However, the preceding embodiments are notintended to limit the present invention in terms of an apparatus towhich the present invention is applicable. That is, the presentinvention is also applicable to other image forming apparatuses than aprinter. For example, the present invention is also applicable to acopying machine, a facsimile machine, and multifunction machine capableof performing two or more functions of the abovementioned machines.Moreover, the present invention is also applicable to a monochromaticimage forming apparatus.

While the present invention has been described with reference toexemplary embodiments, it is to be understood that the invention is notlimited to the disclosed exemplary embodiments. The scope of thefollowing claims is to be accorded the broadest interpretation so as toencompass all such modifications and equivalent structures andfunctions.

This application claims the benefit of Japanese Patent Applications Nos.2015-111982 filed on Jun. 2, 2015 and 2016-078999 filed on Apr. 11,2016, which are hereby incorporated by reference herein in theirentirety.

What is claimed is:
 1. An inputting device having a push type key, saidinputting device comprising: a base member including a main bodyportion, a key portion having an operation surface to be pushed by anoperator, and a first elastic portion and a second elastic portion whichconnect between said main body portion and said key portion; and anelectrical equipment substrate provided on a back side of said basemember, said electrical equipment substrate includes an operatingportion acted on by said key portion when said key portion moves;wherein said first and second elastic portions have symmetricalconfigurations with respect to a first phantom line passing through acentral portion of said key portion, as seen in a directionperpendicular to said operation surface, wherein said operating portionis disposed at a position closer to said first elastic portion than tosaid second elastic portion, and wherein said base member is providedwith a third elastic portion connecting said key portion with said mainbody portion or with said second elastic portion in a side of saidsecond elastic portion with respect to the first phantom line.
 2. Aninputting device according to claim 1, wherein said third elasticportion has a length smaller than that of said first elastic portion. 3.An inputting device according to claim 1, wherein said base member isprovided with a fourth elastic portion connecting said key portion withsaid main body portion in a side opposite from a side having a centralportion of said operating portion with respect to a second phantom lineperpendicular to said first phantom line, as seen in a directionperpendicular to said operation surface.
 4. An inputting deviceaccording to claim 1, wherein said electrical equipment substrate isprovided with a light emission element illuminating said key portion. 5.An inputting device according to claim 4, wherein said light emissionelement is disposed at a position closer to the central portion of saidkey portion than said operating portion, as seen in a directionperpendicular to said operation surface.
 6. An inputting deviceaccording to claim 4, wherein said light emission element is disposed ata position which is the same as the central portion of said key portion,as seen in a direction perpendicular to said operation surface.
 7. Aninputting device according to claim 4, wherein said key portion isprovided with a light transmitting portion for passing light from saidlight emission element.
 8. An inputting device according to claim 4,wherein said key portion is provided with a part having a lighttransmitting portion for passing light from said light emission element.9. An inputting device according to claim 1, wherein said key portion isfor switching between a state in which a wireless local area network isusable and a state in which the wireless local area network isnon-usable.
 10. An image forming apparatus comprising: an image formingstation configured to form an image on a recording material; and aninputting device having a push type key, said inputting deviceincluding, a base member including a main body portion, a key portionhaving an operation surface to be pushed by an operator, and a firstelastic portion and a second elastic portion which connect between saidmain body portion and said key portion, and an electrical equipmentsubstrate provided on a back side of said base member, said electricalequipment substrate includes an operating portion acted on by said keyportion when said key portion moves, wherein said first and secondelastic portions have symmetrical configurations with respect to aphantom line passing through a central portion of said key portion, asseen in a direction perpendicular to said operation surface, whereinsaid operating portion is disposed at a position closer to said firstelastic portion than to said second elastic portion, and wherein saidbase member is provided with a third elastic portion connecting said keyportion with said main body portion or with said second elastic portionin a side of said second elastic portion with respect to the phantomline.